Spencer has received a blood transfusion from Nancy Writebol, a missionary and one of the few survivors of the disease.

Traffic drives past Bellevue Hospital where Dr. Craig Spencer is currently recovering from Ebola in New York.Reuters

Dr Craig Spencer, the fourth person to contract the deadly virus Ebola in the US, has started showing some signs of improvement.

Through a written statement posted on Saturday, 1 November, the New York City Health and Hospitals Corporation announced that the 33-year-old, who is being treated at the Bellevue Hospital in New York, is responding well to the treatment and is in a stable condition, Reuters reported.

"Based on our patient's clinical progress and response to treatment, today HHC is updating his condition to 'stable' from 'serious but stable'," the statement read. "The patient will remain in isolation and continue to receive full treatment."

During the treatment, Spencer has received a blood transfusion from Nancy Writebol, a missionary and one of the few survivors of the disease. He also reportedly received an antiviral medication and plasma.

Spencer, a physician at the Columbia Presbyterian Hospital, contracted Ebola in Guinea, but tested positive only on 23 October, nearly one week after he reached his home in the Harlem section of New York.

He was one of the health workers in the Doctors Without Borders clinic, who volunteered to provide Ebola care in the West African country.

Reports show that he treated his last Ebola patient on 12 October and boarded a flight to the US two days later. He reached John F. Kennedy International Airport on 17 October, according to The Associated Press and ABC News.

The doctor came under severe criticism as he visited a couple of public places after returning from Guinea. It included a bowling alley in Brooklyn, a restaurant in Manhattan and three subways.

However, authorities urged the public not to get panic as Spencer was not displaying any symptoms of the disease during that time. They said that Ebola spreads only through direct contact with the bodily fluids of an infected person, and not through the air.

"There is no reason for New Yorkers to be alarmed," New York Mayor Bill de Blasio, said while addressing a press conference in Bellevue, Reuters reported. "Being in the same subway car or living near someone with Ebola does not in itself put someone at risk."

Dr Spencer is the only person in the US suffering from the deadly virus. The two Texas Health Presbyterian hospital nurses, Nina Pham (26) and Amber Vinson (29), who contracted Ebola while taking care of Thomas Eric Duncan, the first Ebola victim in the country, were released after they tested negative last month.